A group of hardcore runners was extolling the virtues of Vibram Five Fingers, a brand of footwear that features a slender rubber sole and a separate pocket for each toe, when someone remarked that they found the Vibrams hard to wear and thought they made their feet look like a Muppet's. This stopped the conversation cold. You'd have thought they claimed to support terrorism against puppies.

Barefoot or minimalist shoes have garnered quite the rabid fan base in the past few years. The credit for making them mainstream goes to Chris McDougall, author of the excellent book "Born to Run," which explores the life and running habits of the Tarahumara Indians of Mexico's Copper Canyon, arguably the greatest distance runners in the world.

In the book, McDougall explains how running sans shoes or in minimal footwear has taught him to shorten his running stride to a more natural length and land closer to the ball of his foot, thereby allowing his feet and ankles to become the flexible shock absorbers they were meant to be.

This, he claims, is closer to the way our primal ancestors ran when they hunted and gathered for a living, compared to running in a typical modern running shoe, which forces your weight backward so you tend to strike onto your heel as you land. He and other barefoot proponents believe that retraining your 21st century foot to stay up off the heel will result in fewer sore knees and swollen ankles.

Not everyone is on board with this idea however. It's a hotly debated subject that apparently will get you snubbed at parties. It's also started some pretty spirited disagreements in the lab.

"When you run closer to the forefoot as you do with barefoot running or when you practice a barefoot running style you lose what we call the initial impact peak, which is the force that shoots up through your ankles, knees and hips and this might be injury protective," said Reed Ferber, director of the Running Injury Clinic at the University of Calgary in Canada. "That being said, you also shorten your stride length, so you take more footfalls. This means you'll absorb more maximum load over time, which could potentially be more injury causative."

Do Running Shoes Affect Injury Risk?

Studies have found that the average barefoot runner's stride is about seven centimeters shorter than normal. Over the course of a marathon, that translates to about 7,000 additional footfalls above the 40,000 steps a typical racer will take to cover the 26.2-mile distance.

"There's less force per step, but that's a lot of extra steps to take where something potentially can go wrong," Ferber said.

Though no major studies have been completed to show whether barefoot runners are sidelined more or less often than those wearing conventional shoes -- Ferber's lab currently has one under way -- based on the evidence so far, Ferber said he feels it's a push. "I suspect they probably trade one type of injury for another."

Irene Davis, professor in the program of physical therapy at the University of Delaware, couldn't disagree more.

"I believe that when you take your shoes off, you run the way you are meant to run," Davis said. "And when you do that you will not land on your heel for one simple reason -- it hurts!"

Davis, herself a passionate barefoot runner, says that whether you believe in God, Mother Nature or evolution, we simply weren't given enough cushioning to get away with too much repetitive pounding on our heels.

She and several colleagues recently looked at Kenyans who are lifelong barefoot runners, U.S. barefooters and those who wear orthodox running shoes to compare running style and impact forces between the three groups.

In a paper they published in the journal Nature earlier this year, the team reported that the rear-foot strike of shod runners is like being hit on the foot with a hammer with about one and a half to three times your body weight, something that would cause a lot of pain if you removed all that supportive EVA cushioning the shoe provides.

In contrast, the forefoot strike of a shoeless runner had virtually no impact at all and their ankles were more flexible than those of the heel-striking shoe wearers which could potentially provide protection against common stress injuries.

More Research Needed on Minimalist Shoes

Though Davis thinks many runners would benefit from tossing aside their expensive kicks and running au natural from the ankles down, even she admits that more study is needed and you should stick with what works for you.

"The people who get injured and give up running, that's who I'd like to see give this a try and who I think can benefit most from going barefoot or trying a minimal shoe," she said.

As for me, I own up to the Muppet remark. I think the Vibrams look ridiculous and trying to sort all of my uncooperative appendages into the right compartments isn't worth the effort. Despite this, I fall squarely in the minimalist camp. I've always worn the lightest shoes I could find my entire running career yet I've barely had so much as a tweaked knee since high school, knock on wood.

My choice is the Plain Jane New Balance 100's. The tread is lighter than a piece of no-carb toast and the outsole is practically weightless. Relative to many other models, they are dirt cheap too.

For the record, Ferber isn't totally against the trend either. He just wants more proof. He's gotten so many questions about it, he's posted a "how to" on his website. Check it out for yourself at http://www.runninginjuryclinic.com/media/Strengthening_Barefoot_Schedule.pdf. Let me know what you think by posting a comment here. And if you do decide to go barefoot, I hope you'll still speak to me.